if [ $1 -gt 12 ]; then
    echo "you had enter > 12" # great than
elif [ $1 -le 12 ]; then
    echo "you had enter < 12" # low and equal
else
    echo "you had enter unexpected word"
fi

# -ne  //no equal
# -eq  // equal
# -lt  // low than
# ge   //great and equal
# le  // low and equal
